Composite quality index of silk cocoons: An application of discriminant analysis

Abstract

The quality of silk cocoons is determined by a number of characteristics. Each of these characteristics measures a different aspect of the quality. In the absence of a single measure for the overall quality, the price of the cocoons is based on one or two characteristics, which are deemed to be most important by the buyer or the seller. It is shown that there is very little correlation between these characteristics. A methodology is developed to create a composite quality index (CQI), which encompasses all the important characteristics. The cocoons are graded into three categories, Low, Medium and High quality based on the CQI. Discriminant analysis is used to map the individual characteristics directly on to the three grades of cocoons. It is shown that the discriminant functions are significant and that the functions are able to classify the cocoons into the grades with a high degree of accuracy. Once the cocoons are graded using the discriminant functions, the buyers and the sellers could negotiate the price with complete information about the overall quality of the cocoons.